SbcCD causes a double-strand break at a DNA palindrome in the Escherichia coli chromosome

Mol Cell. 2008 Mar 14;29(5):644-51. doi: 10.1016/j.molcel.2007.12.020.

Abstract

Long DNA palindromes are sites of genome instability (deletions, amplification, and translocations) in both prokaryotic and eukaryotic cells. In Escherichia coli, genetic evidence has suggested that they are sites of DNA cleavage by the SbcCD complex that can be repaired by homologous recombination. Here we obtain in vivo physical evidence of an SbcCD-induced DNA double-strand break (DSB) at a palindromic sequence in the E. coli chromosome and show that both ends of the break stimulate recombination. Cleavage is dependent on DNA replication, but the observation of two ends at the break argues that cleavage does not occur at the replication fork. Genetic analysis shows repair of the break requires the RecBCD recombination pathway and PriA, suggesting a mechanism of bacterial DNA DSB repair involving the establishment of replication forks.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence*
  • Chromosomes, Bacterial*
  • DNA Breaks, Double-Stranded*
  • DNA Damage
  • DNA Repair
  • Deoxyribonucleases / genetics
  • Deoxyribonucleases / metabolism*
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Exodeoxyribonuclease V / metabolism
  • Exonucleases / genetics
  • Exonucleases / metabolism*
  • Recombination, Genetic

Substances

  • Escherichia coli Proteins
  • SbcC protein, E coli
  • Deoxyribonucleases
  • Exonucleases
  • sbcD protein, E coli
  • Exodeoxyribonuclease V